Amino-fluoranthraquinones and process of making same



United States Patent AMINO-FLUORANTHRAQUINONES PROCESS OF MAKING SAME NoDrawing. Application July 30, 1951, Serial No. 239,402

Claims priority, application Switzerland July 31, 1950 2 Claims. (Cl.260-4381) AND l-amino-6-chloranthraquinone is a known compound which canbe prepared by replacing the sulfonic acid group in1-nitro-anthraquinone-6-sulf0nic acid by a chlorine atom by means ofsodium chlorate, and reducing the nitro group in the resulting1-nitro-6-chloranthraquinone. However, it is not possible to prepareLamino-6-bromanthraquinone in an analogous manner because the sulfonicacid group in the ,B-position scarcely reacts at all with an alkalibromate. The possibility of preparing 1-amino-6-fluoranthraquinone in ananalogous manner from l-nitro-anthraquinone-6-sulfonic acid by way of1-nitro-6-fluoranthraquinone is ruled out, in view of the fact, as isknown, that with the agents available at the present time it is notpossible to exchange a sulfonic acid group for a fluorine atom.

An alternative method for preparing l-amino-G-chloranthraquinoneconsists in treating sodium 6-chloranthraquinone-l-sulfonate in thepresence of sodium nitrobenzene-3-sulfonate with aqueous ammonia at atempera ture below 160 C. (see U. S. Patent No. 2,100,527 of November30, 1937' to Myron S. Whelen). By this method1-amino-6-bromanthraquinone can also be made from sodium6-bromanthraquinone-l-sulfonate. If how ever the treatment with ammoniais carried out at temperatures above 170 C., l zd-diaminoanthraquinoneis obtained directly from sodium- 6-chloranthraquinone-lsulfonate aswell as from sodium 6-bromanthraquinone-1- sultonate, and the samediamino compound is also; obtained when ammonia is reacted in theforegoing manner at a temperature above 170 C. with l-amino-6-chloror-6-bromanthraquinone.

Attempts to prepare 1-amino-6-fluoranthraquinone from2-fluoranthraquinone-5-sulfonic acid by the methods described abovefail, because at temperatures substantially below 170 C., for example,those at which the reaction of 6-chloror 6-bromanthraquinone-l-sulfonicacid to form 6-bromor 6-chlor-l-aminoanthraquinone occurs, as given inthe aforesaid U. S. patent, 2-fluoroanthraquinone-S-sulfonic acid isunexpectedly converted with ease into 1:6-diaminoanthraquinone. In thiscase therefore the fluorine atom is unexpectedly more mobile than thechlorine or bromine atom.

The present invention provides a process whereby1-amino-6-fluoranthraquinone, which is not obtainable by the moreobvious methods referred to above, can be obtained in a simple manner.The process of the invention comprises sulfonating 2-fluoranthraquinonein the presence of a mercury salt, treating the resulting mixture of 6-and 7-fluoranthraquinone-l-sulfonic acid or the6-fluoranthraquinone-l-sulfonic acid isolated therefrom with an alkalichlorate, condensing the resulting chlorofluoranthraquinone or isomericmixture with an aromatic sulfonamide and hydrolysing the resulting arylsulfonyl amino-fluoranthraquinone or isomeric mixture.

The sulfonation of the 2-fluoranthraquinone in the presence of a mercurysalt may be carried out with advantage by means of fuming sulfuric acid(oleum) at a raised temperature, for example at a temperature rangingfrom 2,720,533 Patented Oct. 11, 1955 50150 C. The sulfonic acid groupenters the 5-position of the anthraquinone nucleus and partly also the8-position, so that the sulfonation mixture contains6-fluoranthraquinone-1-sulfonic acid (about 55 per cent at least) and7-fluoranthraquinone-l-sulfonic acid (up to about 45 per cent).Depending on whether 6-fluoranthraquinonel-sulfonic acid free fromisomer is desired or whether a smaller or larger amount of7-fluoranthraquinone-1-sulfonic'acid is permissible or desired as aby-product (for example in order to utilize as much as possible of thereacted 2-fiuoranthraquinone in cases where the isomeric mixture isequally suitable for the purpose in View), the sulfonation product maybe more or less completely separated from the reaction mixture, which isadvantageously previously diluted with water, by conversion into thealkali salt sparingly soluble in dilute acid, for example, the sodiumsalt.

Replacement of the sulfonic acid group by a chlorine atom by means of analkali chlorate such as potassium or sodium chlorate is carried out by amethod in itself known, advantageously in an aqueous medium containinghydrochloric acid at a raised temperature, advantageously at 100 C.

The reaction of the resulting chloro-fluoranthraquinone with thearomatic sulfonamide, for which purpose a simple sulfonamide such, forexample, as para-toluene sulfonamide may be used, may also be carriedout by methods in themselves known, for example, by heating the tworeactants together in the presence of sodium acetate and copper acetate.The hydrolysis of the resulting arylsulfonylamino compounds to theamines is advantageously carried out by gently heating in concentratedsulfuric acid.

The invention also includes a process for the manufacture of1-chloro-6-fluoranthraquinone or a mixture of it with1-chloro-7-fluoranthraquinone, respectively, wherein2-fluoranthraquinone is sul fonated in the presence of a mercury salt,and the resulting mixture of 6- and 7- fluoranthraquinone-l-sulfonicacid or the 6-fluoranthraquinone-l-sulfonic acid isolated therefrom istreated with an alkali chlorate.

1-amino-6-fluoranthraquinone, obtainable by the process of theinvention, which may also contain some 1- amino-l-fluoranthraquinone andalso l-chloro-6-fiuoranthraquinone or l-chloro-dfluoranthraquinonecontaining some of the 1:7-isomer, are new and valuable intermediateproducts which are especially suitable for the manufacture ofanthraquinone vat dyestuffs. Dyestuffs of this kind are disclosed in ourcopending application, Ser. No. 239,401, Patent No. 2,685,591 filed oneven date herewith.

The following examples illustrate the invention, the parts andpercentages being by weight:

Example 1 93 parts of pure 2-fluoranthraquinone are introduced into amixture of 192 parts of oleum, containing 24 per cent. of free S03, 34parts of oleum containing 65 per cent. of free $03, and 2 parts ofmercury sulfate at 60-65 C., while stirring. The temperature is thenraised to C. in the course of 1 hour, and maintained at 125130 C. untilthe sulfonation is complete. The whole is then poured into 3000 parts ofwarm water, which contains 2 parts of sodium chlorate, and the mixtureis heated to the boil and filtered with suction. The filtrate is mixedhot with about 50 parts of sodium carbonate, and allowed to stand atroom temperature for 24 hours. The fluoranthraquinone sulfonic acidprecipitated in the form of colorless crystals is separated by filteringwith suction, and washed with saturated sodium sulfate solution, anddried.

A solution of parts of sodium chlorate in 330 parts of Water isintroduced dropwise into a solution of 37 parts of the resulting sodium2-fluoranthraquinone-5-sulfonate in 3000 parts of water and 240 parts ofconcentrated hydrochloric acid in the course of 2 hours at 90-95 C.,while stirring. Stirring is continued at 9095 C. until no furtherchloro-derivative precipitates. The whole is then filtered hot, andwashed with boiling water and dried. The crude1-chlor-6-fluoranthraquinone can easily be recrystallized from glacialacetic acid, chlorobenzene or ortho-dichlorobenzene. It crystallizes inpale yellow needles and dissolves in concentrated sulfuric acid with anintense yellow coloration.

Analysis-CnI-IsOzClF: Chlorine (calculated) 13.62%; Fluorine(calculated) 7.29%; Chlorine (found) 13.65%; Fluorine (found) 7.4%.Practically pure 1-chloro-6- fluoranthraquinone melts at 191-192 C.

A mixture of 200 parts of 1-chloro-6-fiuoranthraquinone, 160 parts ofpara-toluene sulfonamide, 80 parts is mixed with more than 50 parts ofsodium carbonate,

for example, about 100 or 150 parts, and there is obtained of anhydroussodium acetate, 4 parts of copper acetate and 1400 parts of nitrobenzeneis slowly heated up to 170 C. The mixture is then stirred at 170175 C.for 2 hours and then for a further 2 hours at 190-495 C. After cooling,the whole is filtered with suction, and the filter residue is washedwell with boiling alcohol and sole, and then forms brilliant redneedles, which dissolve with a yellow coloration in concentratedsulfuric acid. The practically pure 1-amino-6-fiuoranthraquinone soobtained corresponds to the formula and melts at 208-209 C.

Example 2 The dilute reaction mixture obtained by the sulfonation of2-fluoranthraquinone as described in Example 1 a mixture offluoranthraquinone sulfonic acids, which apparently contains aconsiderable amount of the 7-isomer. By the action of chlorate upon thehydrochloric acid solution of this sulfonic acid mixture a mixture ofchlorofluoranthraquinone is obtained, which melts at a markedly lowertemperature than the pure 1-chloro-6-fluoranthraquinone. This mixture ofchloro-fluoranthraquinones can be converted by the method described inExample 1 into a mixture of amino-fluoranthraquinones. The resultingmixture is also a valuable intermediate product for the manufacture ofdyestuffs.

What We claim is:

1. A process for the manufacture of an u-amino-fifiuoranthraquinone, theamino group and fluorine atom of which are bound to differentsix-membered rings of the anthraquinone nucleus, which process comprisessulfonating in the presence of a mercury salt Z-fiuor-anthraquinone,treating the resulting B-fluoranthraquinone-a-sulfonic acid with analkali chlorate, condensing with an aromatic sulfonamide the resultinga-chloro-[B-fluoranthraquinone, and hydrolysing the so obtained a-arylsulfonyl amino-pfluoranthraquinone.

2. A process for the manufacture of an a-amino-fifiuoranthraquinone,which comprises sulfonating in the presence of a mercury salt2-fiuor-anthraquinone, isolating substantially from the resultingmixture of 6- and 7-fiuoranthraquinone-l-sulfonic acid the6-fluor-anthraquinonel-sulfonic acid by converting the sulfonic acids inan aqueous medium into alkali salts and separating from the resultantmixture the precipitated 6-fluor-anthraquinonel-sulfonic acid andtreating it with an alkali chlorate, condensing with an aromaticsulfonamide the resulting 1 chlor-6-fiuoranthraquinone, and hydrolysingthe so ob tained 1-arylsulfonylamino-6-fluoranthraquinone.

References Cited in the file of this patent UNITED STATES PATENTS743,664 Schmidt Nov. 10, 1903 1,761,620 Deinet June 3, 1930 1,810,011Gubclmann et al. June 16, 1931 1,924,664 Thomson et a1. Aug. 29, 19332,013,657 Johnson Sept. 10, 1935 2,074,306 Whelen Mar. 16, 19372,100,527 Whelen Nov. 30, 1937 2,134,654 Lulek Oct. 25, 1938 2,181,034Whelcn Nov. 21, 1939

1. A PROCESS FOR THE MANUFACTURE OF AN A-AMINO-BFLUORANTHRAQUINONE, THEAMINO GROUP AND FLUORINE ATOM OF WHICH ARE BOUND TO DIFFERENTSIX-MEMBERED RINGS OF THE ANTHRAQUINONE NUCLEUS, WHICH PROCESS COMPRISESSULFONATING IN THE PRESENCE OF A MERCURY SALT 2-FLUOR-ANTHRAQUINONE,TREATING THE RESULTING B-FLUORANTHRAQUINONE-A-SULFONIC ACID WITH ANALKALI CHLORATE, CONDENSING WITH AN AROMATIC SULFONAMIDE THE RESULTINGA-CHLORO-B-FLUORANTHRAQUINONE, AND HYDROLYSING THE SO OBTAINED A-ARYLSULFONYL AMINO-BFLUORANTHRAQUINONE.